In Flight Radome Error Compensation Through Simulated Test Data

Abstract

This work deals with Algorithm for In Flight Radome Error Compensation with simulated data of radome test result for both In Plane Error and Cross Plane Error which are obtained as function of kinematic look angles. The se data are generally stored in On -Board Computer of either Interceptor or Seeker for compensation. Accurate information of kinematic look angles is required for proper interpolation of stored data. Measured gimbal angles lag kinematic gimbal angles throug h track loop time constant, which can be time varying depending on noise content and tracking accuracy of measured sight line rate. In this paper, measured gimbal angles are utilized for computation of radome errors from look up table for compensation. Ear lier results suggest that compensation within track loop yields better performance compared to compensation outside track loop. In this paper it is shown that, performance of homing loop for outside track loop compensation when computed radome errors are m odified by a suitable filter, is quite close to performance with radome error compensation inside track loop. This makes Interceptor system more reliable because in the event of any breakage of radome, spare one can fit in and corresponding test data can b e easily inserted in Interceptor OBC for accurate compensation rather than tampering sensitive software of Seeker OBC for inside track loop compensation. Suitable formulae are also derived for radome errors in 3 -D engagement scenario comprising both In -Pla ne and Cross Plane Errors. Additional results are also derived showing how In Plane and Cross Plane Error characteristics of radome covering its full engagement geometry obtained by experiment can be utilized for on -board compensation. In all these results , realistic simulated seeker noise profile, gimbal angle noise are utilized to claim for practical feasibility of this work.